Such a method is known from the international patent application PCT/NL97/00624. This publication describes the use of peptides derived from filaggrin, and which comprise citrulline or an analogue thereof for the detection of autoantibodies from patients suffering from rheumatoid arthritis. The peptides used are therefore suitable for diagnostic applications, and compared with up to then, make a more reliable detection possible. More in particular this concerns a decrease in false-positives, i.e., a higher specificity. In addition, the sensitivity is relatively high. One peptide, indicated as cfc1, was recognized by 36% of the sera from patients suffering from rheumatoid arthritis. The cyclic variant of the peptide appeared to be recognized even better (63%).
A method according to the preamble is also known from the international patent application PCT/FR00/01857. This publication describes the use of peptides derived from fibrin or fibrinogen, and which comprise citrulline or an analogue thereof for the detection of autoantibodies from patients suffering from rheumatoid arthritis.
PCT/EP98/07714 describes the use of synthetic peptides derived from (pro)filaggrin for the diagnosis of rheumatoid arthritis. This application also describes synthetic peptides derived from human vimentin, cytokeratin 1, cytokeratin 9 and other intermediary filament proteins.
However, the above-mentioned methods still only detect a limited number of all the patients suffering from rheumatoid arthritis. Therefore there is a strong need for a method by which an increased sensitivity can be achieved while maintaining a substantially equal or even improved specificity.